Authorities in West Bengal and Orissa raced on Thursday to evacuate tens of thousands of people from vulnerable coastal areas as a powerful cyclone producing winds up to a speed of 280 km per hour closed in.

The West Bengal government has alerted the Army to remain on stand by, finance minister Ashim Dasgupta said. The coastal areas in the two states are expected to be hit by six to seven metre high tidal waves. Dasgupta said at least 10 lakh people in West Bengal may have to be evacuated to safer places.

The government has allocated Rs 15 crore to meet all exigencies. Cyclone Sidr, currently moving north over the Bay of Bengal and packing ferocious winds and torrential rains, is expected to hit land around midnight with six coastal districts in Orissa and five districts in West Bengal likely to face its fury. Kolkata city is also likely to be affected.

The first area to be lashed will be around the Sunderbans, a vast mangrove forest straddling the India-Bangladesh border. The coastal area is also home to many poor fishing communities as well as the endangered Royal Bengal tigers.

West Bengal Regional Met office director G C Debnath said the cyclone was intensifying and moving fast towards the state coast gathering momentum.

The weather office has alerted the state administration to the possibility of severe damages in the coastal areas. "The state administration had been asked to shift the people of the coastal areas to safer locations," Debnath said.

The civic authorities have set up a crisis management group, West Bengal Chief Secretary P R Ray said ,adding that alert had already been issued.

Debnath said alert warning to Sagar Island had already been issued. Fishermen have been advised not to venture into the sea for fishing and to stay alert.

The Tropical Storm Risk Centre has put the cyclone in Category 4 with windspeeds reaching upto 225-280 km per hour, a US consulate communique said in Kolkata.

The Orissa government has begun evacuation of people from sea-side villages in six districts. Though the cyclone moved towards West Bengal-Bangladesh region, the Cyclonic Warning Centre warned that under its impact tidal waves up to a height five to six feet above normal tide are likely in coastal areas of Balasore, Bhadrak, Kendrapara and Jagatsinghpur districts.

"Tidal surge might be experienced at the time of the storm crossing the coast," CWC Director Sarat Sahu said, adding that a gale with wind speed of 90-120 kmph was also likely to occur very soon.

As the system approaches the coast, a gale with wind speed reaching 120-150 kmph was likely along and off north Orissa coast, while a gale with wind speed reaching 90-120 kmph along and off south Orissa is likely by Friday, Sahu said and warned that "sea condition will be very high -- over 14 m".

Special Relief Commissioner (SRC) N K Sunaday said directions were already given for evacuation of people living in sea-side villages in six districts.

"Evacuation has already begun in Balasore, Bhadrak, Kendrapara, Jagatsinghpur, Puri and Ganjam districts," he said.The government machinery had geared up to evacuate people from nearly 500 villages living on the 480-km stretch of Orissa coast, official sources said.

While people living within 10 km from the coast in Balasore district were asked to shift to safety, people in Kendrapara and Jagatsinghpur districts were asked to move at least eight km and seven km from the sea when the system crosses Sagar island, the Relief Commissioner said.

He said a number of villages within six and five km from sea in Puri and Ganjam districts were also being evacuated.Public announcement system was being used to ask the people to move to safer places like cyclone shelters or nearby educational institutions.

The CWC also warned about extensive damage to kutchha houses and partial disruption of power supply and communication lines.

"Minor disruption of rail and road traffic might also occur," it said. While advising fishermen not to venture into the sea, the CWC suggested hoisting of distant warning signal of two at Paradip, Gopalpur, Chandbali and Puri.